Windows 10: Microsoft Safety Scanner, normal to show infected files, when finished says it detected 0?

OS Name Microsoft Windows 11 Pro Version 10.0.22631 Build 22631 Other OS Description Microsoft Corporation System Type x64-based Default string Processor 12th Gen IntelR CoreTM i9-12900KF, 3200 Mhz, 16 Cores, 24 Logical Processors e UEFI Platform Role Desktop Secure Boot State On Windows Directory C:\Windows System Directory C:\Windows\system32 Boot Device \Device\HarddiskVolume3 Hardware Abstraction Layer Version = "10.0.22621.2506" Installed Physical Memory RAM 128 GB Total Physical Memory 128 GB Available Physical Memory 93.0 GB Total Virtual Memory 136 GB Available Virtual Memor

:)

 

microsoft safety scanner showing same files infected

If you're seeing these 15 infected files only during the scanning process listed next to the line titled 'Files infected', then that's a well-known situation that confuses many who don't understand how this, or any other Microsoft malware scanner truly operates.

During the scan itself, the Safety Scanner displays this Files infected counter that includes all of the individual fragments of potential malware it has detected using the signatures contained within the downloaded file. However, once the scanning portion has reached roughly 95% completed (per the progress bar), the scanning tool (and most other Microsoft scanners like Defender) perform a 'phone home' request using a cloud service also known as MAPS (Microsoft Active Protection Service).

What this MAPS request does for the Safety Scanner is allows it to not only verify that the items detected aren't actually a false positive detection, but also that the remediation (fix) for these particular items hasn't been updated or changed, as well as that the combination of items are truly 'active' malware and not simply leftover fragments of an already 'dead' or failed malware attack, which commonly occurs for example when a website file download is either aborted or fails to truly operate due to protections like SmartScreen filter or others built into either the Edge browser or Windows itself.

Once the MAPS process is complete, the reporting and any remediation instructions or other items required for the Safety Scanner to finish its process are returned to the client via the cloud and performed locally, at which point the Safety Scanner UI displays a final reporting of whether any truly active malware was detected and/or removed, which in many cases results in 0 (no) active items having been found.

If this no active malware infections result is what you're seeing, that's totally appropriate, since as the above description shows, the initial detections of 15 'Infected files' is only preliminary, so it's this final determination by MAPS that truly matters.

Rob

 

Microsoft Safety Scanner > Files Infected count

There's a bit of a UX problem with the scanner. As it is running it may encounter files that are suspected of being infected but indicate a count as: "Files Infected: XX"

This suggests the files are infected and apparently no list of these potentially infected files are provided.

1. Change the label to "Possible Infected Files"
   
2. Write to the msert log the list of possibly infected files for further review/action.
   

I say this as I let the tool run for over 3 hours, racking up over 20 "Files Infected". My computer was disconnected from the Internet during the scan. So I was surprised that the files in question were somehow "cleared" despite a lack of Internet connection.

From the log:

Results Summary:

----------------

No infection found.

Failed to submit MAPS report: 0x80072EE7

Failed to submit clean hearbeat MAPS report: 0x80072EE7

Microsoft Safety Scanner Finished On Sun Apr 30 13:20:56 2023

If the suspected files couldn't be submitted, then how were they cleared? Which files were suspected?

I appreciate the tool just cannot trust the results.

 

Microsoft Safety Scanner (64-bit) scanning showing 164 infected files however final scan results says 0 detected

Hi. I'm David, and I'm happy to help you.

Microsoft Safety Scanner may report that it found threats before the end of the scan and show no detection at the end. What happens is that it finds possible infections, but at the end of the scan, it does a full check on these items, and it may find that there is no infection.

This is normal behavior for Microsoft Safety Scanner.

Therefore, if at the end of the scan, no threats were reported, nothing was found by Microsoft Safety Scanner.

Feel free to ask back any questions.